Recirculating system with reversible flow centrifugal pump



1965 w. H. GROWALL ETAL 3,220,553

REGIRCULATING SYSTEM WITH REVERSIBLE FLOW CENTRIFUGAL PUMP 4 Sheets-Sheet 2 Filed July 5, 1962 b WH.GA0WALL \0 BY AMES W/SEMA/V jrfl h f gi Nov. 30, 1965 w. H. GROWALL ETAL 3,220,553

RECIRCULATING SYSTEM WITH REVERSIBLE FLOW CENTRIFUGAL PUMP Filed July 5, 1962 4 Sheets-Sheet 5 c/AMES W/sEM /v 7 f v i n. TT'ORNEY' Nov. 30, 1965 w, H, GROWALL ETAL 3,220,553

RECIRGULATING SYSTEM WITH REVERSIBLE FLOW CENTRIFUGAL PUMP Filed July 5, 1962 4 Sheets-Sheet 4 INVENTORS W/7.G/P0WALL 0444/59 W/ SEMH/V United States Patent 3,229,553 RECHKCULATTNG SYSTEM WITH REVERSZBLE FLOW CENTRFUGAL PUMP William H. Growall, 2970 W. Davison Ave., and Eames Wiseman, 843 Pingree Ave, both of Detroit, Mich. Filed July 5, 1962, Ser. No. 207,565 9 Claims. (Cl. 21(l108) This invention relates to a novel recirculating system for liquids by means of which a liquid, in a receptacle or container, can be recirculated and filtered or otherwise cleansed or treated during the recirculation thereof.

More particularly, it is an object of the invention to provide a recirculating system which may be reversed for backwashing or cleansing a filter of the system, or for otherwise removing dirt or other foreign particles which may have accumulated therein, and whereby during the backwashing cycle the recirculated liquid is discharged to waste automatically.

Still a further object of the invention is to provide a recirculating system including a novel reversible centrifugal pump having novel means whereby the direction of flow therethrough is reversed automatically by reversal of the direction of rotation of an impeller thereof.

Still a further object of the invention is to provide a novel valve and trap structure connected to and associated with the centrifugal pump and which operates automatically in response to a vacuum or pressure from the pump, to provide a closed system whereby the liquid, after passing through the system and being cleansed or otherwise treated, is returned to the source of supply of the system, or automatically discharged to Waste when the pump is reversed for accomplishing the backwashing cycle.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrating a presently preferred embodiment thereof, and wherein:

FIGURE 1 is a fragmentary vertical sectional view, partly in side elevation and partly broken away, illustrating a preferred embodiment of tne complete system;

FIGURE 2 is a fragmentary longitudinal sectional view, on an enlarged scale, illustrating a part of the systern;

FIGURE 3 is an enlarged sectional view of the reversible centrifugal pump, taken substantially along the line 3--3 of FIGURE 4;

FIGURE 4 is a sectional view taken substantially along the line 44 of FIGURE 3 and showing a part of the reversible electric motor utilized for driving the pump impeller;

FIGURE 5 is a sectional view of the pump, taken substantially along the line 5-5 of FIGURE 4, and on an enlarged scale;

FIGURE 6 is an enlarged sectional view taken transversely through the front of the pump, substantially along a plane as indicated by the line 6-6 of FIGURE 4;

FIGURE 7 is a fragmentary sectional view, on an enlarged scale, taken substantially along the line 7-7 of FIGURE 5;

FIGURE 8 is a fragmentary sectional view illustrating a detail of the pump;

FIGURE 9 is a fragmentary sectional view taken substantially along the line 99 of FIGURE 3;

FIGURE 10 is a cross sectional view of the trap struc ture taken along the line 1010 of FIGURE 2;

FIGURE 11 is a front elevational view, partly broken away, of another embodiment of the pump impeller;

FIGURE 12 is a sectional view thereof, taken along the line 12-12 of FIGURE 11;

FIGURE 13 is a fragmentary sectional view taken substantially along a plane as indicated by the line 1313 of FIGURE 11, and

FIGURE 14 is a diagrammatic view of the electric circuit of the system.

Referring more specifically to the drawings, the recirculating system in its entirety and as illustrated in FIG- URE 1 is designated generally 15. The system 15 includes a container 16, only a portion of which has been illustrated and which contains a liquid 17. For the purpose of the description, the container 16 may constitute a swimming pool, for which the recirculating system 15 is pri- :marily adapted; however, as the description proceeds it will become apparent that the recirculating system is equally well adapted for numerous other uses and may be associated with numerous other liquid sources besides the liquid 17 contained in the pool body or receptacle 16. A trap and valve structure, designated generally 18, has an inlet 19 to which a conduit 20 connects. The trap structure 18 may be located in an enclosure 21 and the conduit 2% may extend through a wall thereof into a chamber 22 which forms an extension of the pool or container 16 and in which is accommodated a leaf strainer 23, which may be formed of perforated sheet metal. The other end of the conduit connects with and opens into one end of the leaf strainer 23, and said conduit and the major portion of the leaf strainer are disposed within or submerged by the liquid 17. The trap and valve structure 18 has a waste outlet 24 at its opposite end from which a waste pipe 25 leads through a wall of the housing 21. The structure 18 includes a trap 26, located near and beneath the outlet 24. The trap and valve structure 18 has an upwardly projecting port 27, disposed between the inlet 19 and trap 26, to which is connected one end of a conduit 28. The conduit 28 extends upwardly through a cover 29 which is detachably mounted on and closes the top of the housing 21 and the top of the chamber 22.

A base 30 is supported on the cover 29 and provides a support for a reversible centrifugal pump 31 and a filter housing or casing 32. The pump 31 has two nipples 33 and 34 at the top thereof, and the other end of the couduit 28 connects with the nipple 33 while one end of a conduit 35 connects with the nipple 34 for interposing the pump 31 in the recirculating system.

The casing 32 has a horizontal partition wall 36 defining, with par-ts of the casing disposed therebeneath and thereabove, a small bottom chamber 37 and a large upper chamber 38. An upstanding flanged passage, formed in the partition 36, connects the chambers 37 and 38, and said passage 39 defines a neck around which the open end 40 of a filter bag 41 is secured by a clamp 42. The other end of the conduit 35 opens into the chamber 38, and one end of a conduit 43 communicates with and extends from the lower chamber 37 and said conduit 43 has an opposite end opening downwardly into the liquid 17 of the pool or container 16.

The normal recirculating flow, as will hereinafter be more fully described, of the system 15 is from the pool or container 16 through conduit 29, trap structure 18, conduit 28, pump 31, conduit 35, chamber 38, passage 39, chamber 37 and conduit 43, back to the pool or source 16. When the pump 31 is reversed the direction of flow is in the opposite direction, from the pool or source 16 through conduit 43, filter casing 32, conduit 35, pump 31, and conduit 28 to the valve and trap structure 18. However, as it will hereinafter be described, on this reverse fiow or backwashing cycle the liquid after entering the structure 18 from the conduit 28 flows through the trap 26 to and through the outlet 24 and conduit 25 from which it is discharged to waste.

The pump 31 as illustrated in detail in FIGURES 3 to 9 includes a casing section 44, as best illustrated in FIGURES 3 and 4, having a bottom rear wall 45 which is provided with a rearwardly extending annular flange 46. The forward end of a conventional electric motor 47 is secured to the flange 46 by fastenings 48. The wall 45,flange 46, and the forward end of the casing of the motor 47 combine to form a chamber 49. The wall 45 has a boss 50 extending into the chamber 49 and which aligns with a boss 51 of the motor casing, which likewise extends into said chamber. The bosses 50 and 51 contain antifriction bearing means 52 and 53, respectively, for journaling the armature shaft 54, of the motor 47, which extends therethrough into the lower part of the casing section 44.

The bottom part of the casing section 44 has an arcuate channel 55, formed in part by the rear wall 45 and by a lower part of a surrounding front flange 56. The casing section 44 has a top wall 57 from which the nipples 33 and 34 project, a rear wall 58, which is inclined downwardly and rearwardly from the top wall 57 and which joins with the flange 46, corresponding side walls 59 and 60, and a central partition wall 61. The lower ends of the side walls 59 and 60 merge with parts of the channels 55, and the forward edge of the partition wall 61 is disposed coplanar with the surrounding front flange 56, as seen in FIGURE 5. The rear section 44 also includes a part 62, as seen in FIGURE 3, which extends from the lower edge of the partition wall 61 and which merges with upper end portions of the channel 55 to define two corresponding upwardly opening passages 63 and 64. The partition wall 61 and the part 62 divide the upper portion of the rear section 44 into corresponding chambers 65 and 66 as seen in FIGURE 3, the ports 33 and 66 open downwardly and upwardly, respectively, into the chamber 65, and the ports 34 and 64 open downwardly and upwardly, respectively, into the chamber 66. The upper ends of the ports 63 and 64 are partially disposed in arcuate bottom front portions 67 of the chambers 65 and 66.

The pump 31 includes a front casing section 68 having a surrounding flange 69 which is secured by fastenings 70 to the flange 56. A sealing gasket 71 is interposed between the flanges 56 and 69. The front section 68 has a forwardly bulged vertically elongated central portion, designated generally 72, which includes an outer wall 73 and an inner wall 74. The part 72 has a V-shaped top portion 75 which is provided with a depending extension 76 forming a partition wall, as best seen in FIGURE 6, which terminates above an opening 77 in the bottom part of the inner wall 74 and which is formed in a rearwardly recessed lower part 78 thereof. An upper part of the inner wall 74 is disposed opposite and parallel to the forward edge of the partition wall 61 and the part 62, and a part of the sealing gasket 71 is clamped between said wall portion 74 and the parts 61 and 62, as seen in FIG- URE 5, to seal the chambers 65 and 66 from one another. The rear wall 74 has openings 79 and 80 located in the upper end of the bulged portion 72, on opposite sides of the V-shaped top portion 75, and which communicate with the chambers 65 and 66, respectively. The bulged portion 72 provides passages 81 and 82, located on opposite sides of the V-shaped portion 75 and wall 76, and separated thereby to the level of the lower edge of the wall 76, which passages lead between. the ports 79 and 77 and the ports 80 and 77, respectively.

A centrifugal impeller, designated generally 83, includes a hub 84 which is secured by a threaded connection 85 to the outer or forward end of the armature shaft 54. The impeller 83 is disposed between a part of the wall 45 and the wall portion 78 and is partially surrounded by channel 55 and partially by an arcuate bottom surface of the housing portion 62, as best seen in FIGURE 3. The hub 84 aligns with the port 77. The impeller 83 includes a rear shroud 86 which extends outwardly from and surrounds a part of the hub 84 and which is located adjacent the rear wall 75, and a plurality of circumferentially spaced radially disposed vanes 87 which are preferably formed integral with the shroud 86 and are disposed between said shroud and the wall 78. The vanes 87 have corresponding convexly bowed side walls 88 extending from arcuately rounded inner ends 89 and which converge and merge at the pointed outer ends 90 of the vanes, so that both sides of the vanes 87 are identical.

The rear wall 58 is provided with corresponding open ings 91 on opposite sides of the partition wall 61 and which open into the chambers 65 and 66. An elastic strip 92, preferably formed of rubber, is disposed across a part of the outer side of the rear wall 58 and over the openings 91 and is in turn covered by an outwardly bowed plate or cover 93. The cover 93 and strip 92 are secured to the rear wall 58, around the two openings 91, by fastenings 94. The cover 93 has a central part 95 between which and an intermediateportion of the rear wall 58 an intermediate part of the elastic strip 92 is clamped, as seen in FIGURE 5, so that end portions of the strip 92, which are disposed over the openings 91 define diaphragms 96. The cover 93 has an outwardly bulged part 97 behind each diaphragm 96, into which said diaphragm can be distended when bulged outwardly from the chamber 65 or 66 thereof. The bulged parts 97 combine with the diaphragms 96, individual thereto, to form chambers 98 which are connected by a passage 99, formed in the intermediate cover portion 95, all as clearly illustrated in FIGURE 5.

Each chamber 65 and 66 contains a valve, designated generally 100, including a rigid plate or leaf 101 having at one end thereof aligned apertured ears or sleeves 102 which are journaled on a shaft 103. The shafts 103 of the two valves have adjacent ends which seat in sockets 104 formed on and opening outwardly of opposite sides of the partition wall 61 near its forward edge. The remote ends of the aligned shafts 103 engage in bores 105 in the side walls 59 and 60, and are held against outward displacement by screws 106 which are threaded into the outer ends of said bores, as seen in FIGURE 7. Each valve plate 101 has depending arms 107, the upper ends of which align with the sleeves 102 and which have openings 108 in their lower ends, as best seen in FIGURE 8. Each valve has a pad 109 formed of rubber or other sealing material secured to an underside thereof by a fastening 110.

A yoke 111 is disposed in each chamber 65 and 66. The intermediate portions of the yokes are secured by fastenings 112 to the diaphragms 96, and the terminals of the legs of the yokes have inwardly projecting trunnions 113 which turnably engage in the arm openings 108, the yoke legs being sprung apart to position the trunnions to be received in the openings. The yoke 111 contained in the chamber 65 straddles the upper portion of the passage 63, while the yoke 111 of the chamber 66 has its legs straddling the passage 64. Said yoke legs and the arms 107 engage with clearance in the recesses 67.

As seen in FIGURES 4, 5 and 9, parts of the sealing gasket 71 are disposed against the inner side of the wall 74 around the ports 79 and 80. As shown in FIGURE 4, the valve 100 in the chamber 66 is in a raised position with the side thereof, opposite to the side carrying the pad or seal 109, disposed to close the port 80 and with the peripheral portion of the plate 101 thereof abutting against the part of the gasket 71 which surrounds the port 80 to provide an effective seal. The two valves 100 are always in opposite positions, so that when the valve 100 of the chamber 66 is closing the port 80, as seen in FIGURES 4 and 5, the valve 100 of the chamber 65 will be in a down position closing the passage 63, as seen in FIGURES 3, 5 and 9. This is the normal position of the valves when the liquid 17 is being recirculated, that is, when the liquid is entering the pump 31 through the port 33 from the conduit '28 and is leaving the pump by the port 34 and conduit 35.

As seen in FIGURE 1, the valve trap structure .18 includes an elongated body 114 one end of which defines the inlet 19 and the other end of which constitutes the outlet 24, and a part of which provides the trap 26. The body 114 has valve seats 115 and 116 facing toward one another and disposed in spaced apart relation to one another, as seen in FIGURE 2. A cover 117 is detachably mounted by fastenings 118 to close an opening 119 in the top of the body 114, between the valve seats 115 and 116. The nipple 27 forms a part of the cover 117. Arms 120 extend downwardly from the cover and have aligned openings 121 in which a rod 122 is slidably supported between and in alignment with the centers of the valve seats 115 and 116. A rigid disc 123 is connected to each end of the rod 122, and a resilient sealing disc 124 is secured to the outer face of each disc 123 by a fastening 125.

The body 114 is laterally enlarged at the bottom part thereof and is provided with an opening 126 which is closed by an outwardly bowed cover 127. A diaphragm 128 is disposed over the opening 126, on the inner side of the cover 127, and said diaphragm and cover are secured to the body 114, around the opening 126 by fastenings 129. A shaft 130 extends across and is supported by the housing 114 between the diaphragm 128 and rod 122 to provide a support for a bellcrank 131 which is mounted to rock thereon. A connecting rod 132 projects from the center of the diaphragm 128 inwardly of the body 114 and is connected at its inner end to one arm of the bellcrank 131 by a pin and slot connection 133. The other bellcrank arm has a bifurcated terminal portion 134 the furcations of which straddle the rod 122, between the hanger arms 129, and are notched or slotted, as seen at 135, to engage the ends of a pin 136 which extends through the rod 122 and outwardly from opposite sides thereof. A compression spring 137 is disposed between the cover 127 and the central portion of the diaphragm 128 for normally urging the diaphragm inwardly to its position of FIGURE 2, for holding the parts in the positions of said view with the left hand valve element 124 seating against the valve seat 116.

A conventional electric switch 138 is shown in FIG- URE 4 for de-energizing and reversing the electric motor 47. When the pump 31 is in operation, the normal position of the switch 138 is as shown in FIGURE 4 with the knob pointer 139 directed toward the pointer 140 designated filter. In this position of the switch 138, the shaft 54 and impeller 83 will revolve counterclockwise, as seen in FIGURE 3, so that a suction is created in the chamber 65 and the port 33 which draws the diaphragm 96 of said chamber inwardly to close the valve 100 thereof over the port 63, as seen in FIGURES 3 and 9. This will cause air to be drawn through the passage 99 to the chamber 98, associated with the chamber 65, for evacuating the air from the other chamber 98 to create a suction therein, for drawing the diaphragm 96 of the chamber 66, into its chamber 98 and distended outwardly of the chamber 66, so that the yoke 111 of said diaphragm will exert an upward pull on the valve arms 107 to swing the valve 180 of the chamber 98 to its up position for closing the upper port 80 and exposing the passage 64, as seen in FIGURE 4. Additionally, this counterclockwise rotation of the impeller 83 will create a pressure in the passage 64 and in the part of the channel 55 extending from the port 77 to the passage 64 and which will produce a pressure in the chamber 66, additionally functioning to cause the diaphragm 96 of said chamber to assume its outwardly distended position of FIGURE 4, for holding the valve 180 in an up position to close the port 80. The suction created in the port 33 will produce a suction in the conduit 28 and in the body 114 and conduit 20 so that the liquid 17, after passing through the leaf strainer 23, will enter the valve and trap structure 18 from the conduit 20 through its inlet 19. This suction in the chamber of the body 114, disposed between the valve seats 115 and 116, draws the diaphragm 128 inwardly of said chamber and as the spring .137 is also urging the diaphragm inwardly, the left hand valve 123, 124 will be maintained against the valve seat 116 so that no liquid can be drawn back from the trap 26. The liquid thus entering the body 114 through its inlet 19, from the pool or source 16, will be drawn through the conduit 28 and port 33 into the chamber 65. As the passage 63 is closed by the valve 100 of the chamber and the passage 79 is opened, the liquid will be drawn from the chamber 65 through the port 79 and downwardly through the passage 81 to the impeller inlet port 77, The liquid will be drawn by the suction of the counterclockwise revolving impeller 83 inwardly or rearwardly through the port 77 and will be propelled by the vanes 89 in a counterclockwise direction upwardly through the channel '55 toward and through the passage 64 into the chamber '66. Any air which may be in the system 15 and which enters the pump 31 through the port 33 will readily rise through the passage 64 into the chamber 66, so that the pump will be self-priming. The pressure produced in the chamber 66 by the counterclockwise rotation of the impeller 83 will maintain the valve 100 of said chamber in its position of FIGURES 4 and 5, closing the port 80, so that all liquid and air entering the chamber 66 must pass outwardly therefrom through the port 34 and conduit 35 to the filter chamber 38. This pressure in the chamber 66 will be effective to maintain the diaphragm 96 thereof distended outwardly. The liquid 17 will be cleansed in passing inwardly through the filter 41 after which it will pass through the passage 39, chamber 37, and conduit 43 back to the pool or source 16.

The system 15 can be periodically backwashed to cleanse the filter 41 and filter chamber 38 by merely moving the control knob of the switch 138 to a position with the pointer 139 thereof directed toward the graduation 141, designated backwash, to reverse the motor 47 so that the impeller 83 will then be driven clockwise, as seen in FIGURE 3. When this is accomplished, the liquid 17 will be drawn from the pool or source 16 through conduit 43, a chamber 37, passage 39, outwardly through the filter 41 into chamber 38 and thence to conduit 35, for washing dirt and other foreign matter from the exterior of the filter element 41 and for flushing this dirt and other dirt which may have accumulated in the chamber 38 from said chamber through the conduit 35 and port 34 into the pump chamber 66. Before the liquid in this reverse circuit of travel from the conduit 43 reaches the pump 31, the suction created in the chamber 66 by the clockwise rotation of the impeller 83 will have drawn the diaphragm 96 of said chamber inwardly so that the yoke 111 thereof will have exerted a downward pressure from right to left on the valve arms 107 for swinging the valve 100 downwardly and away from the port and into a position with its seal 109 engaging and sealing the upper end of the passage 64. This will cause air to pass back through the passage 91 from the chamber 98, behind the chamber 65, to the chamber 98 behind the chamber 66. This suction coupled with the pressure created in the chamber 65 by the clockwise rotation of the impeller 83 will distend the diaphragm 96 of the chamber 65 outwardly thereof and into the cover chamber 98, disposed outwardly of said diaphragm, for swinging the valve of chamber 65 upwardly to expose the passage 63 and to close the port 79, so that the liquid, during the backwashing cycle, can be propelled up the channel 55 through passage 63 and chamber 65 to and through port 33 and conduit 28 to the trap 18. This will create a pressure in the trap body 114 which will cause the diaphragm 128 to be distended outwardly there of into the cover 127 for rocking the bellcrank 131 clockwise, as seen in FIGURE 2, for moving the rod 122 and the valves 123, 124 from left to right to uncover the passage leading to the trap 26 and to seal the inlet 19. Accordingly, the backwash liquid entering the trap 18 through the port 27 will flow through the trap 26, drain outlet 24, and conduit and be discharged to waste, all of which, as is apparent, will be accomplished automatically by merely reversing the position of the switch 138.

Actually, where the manual switch 138 is utilized, the trap 18 may be omitted and a flexible conduit 28 may be employed which can be detachably connected directly to the leaf strainer 23. Thus, before the switch 138 is reversed for accomplishing the backwashing cycle, the conduit 28 can be disconnected from the leaf strainer 23 and positioned to discharge into a drain during the backwashing cycle.

However, for underground installations the trap 18 is utilized and a pressure responsive switch, as shown in FIGURE 3, may be employed in lieu of the switch 138 to make the system 15 completely automatic. As seen in FIGURE 3, a disc 142 has an externally threaded hollow nipple 143 extending from an inner side thereof and which opens therethrough. The nipple 143 engages in a threaded port 144 of the wall 60. Two diaphragms 145 and 146 are disposed on the outer side of the disc 142 and are secured around their peripheries to the disc 142 by fastenings 147 to define a chamber 148 which communicates with the chamber 66 through the nipple 143. A flap valve 149 is disposed in the chamber 148, is secured at one end thereof to the disc 142, and has a small bleeder port 150 formed therein. A rod 151 is secured to the diaphragms 145 and 146 and projects outwardly from the diaphragm 146 and has'a fiat head 152 at. its outer end. A dome-shaped cover 153 is detachably mounted on the disc 142 over the diaphragms 145 and 146. A conventional reversing switch 154 is secured in said cover 153 and has an outwardly projecting swingably mounted switch arm 155. An adjusting screw 156 engages threadedly through the cover 153. One end of a compression spring 157 is secured to the inner end of the screw 156 and the other end of said spring is secured to the switch arm 155 for urging the switch arm to its position of FIGURE 3 against the head 152, in which position the circuit of the electric motor 47 is closed for driving the impeller 83 in a counterclockwise direction, as seen in FIGURE 3, to etfect the normal recirculation of the liquid 17, as previously described. As the filter element 41 becomes partially clogged with dirt, pressure will build up in the chamber 66 and a part of this pressure will pass through the nipple 143 into the chamber 148, with the valve 149 yielding away from the disc 142 to allow the chamber 148 to be readily pressurized. When a sufiicient pressure builds uprto overcome the pressure of the spring 157, the diaphragms 145 and 146 will distend into the cover 153 to cause the arm 155 to swing, with a snap action, from left to right of FIGURE 3 for reversing the electric motor 47 so that the backwashing cycle, as previously described, can be accomplished automatically and with the backwash liquid escaping through the waste outlet 24 of the trap structure 18. The small bleeder port 150 will restrict escape of the pressure from the chamber 148, for maintaining the system operating in the backwashing cycle for a sufiicient time interval to thoroughly cleanse the filter element 41 and chamber 38 before the chamber 148 is depressurized sufiiciently so that the spring 157 can return the parts to their positions of FIGURE 3, to again reverse the motor 47 so that the normal recirculating of the liquid 17 will be resumed.

FIGURE 14 shows a conventional electric circuit which can be utilized with the system and wherein both the switch 138 and the switch 154 are shown interposed between a suitable electric current source and the motor 47. A positive conductor 175 extends from the current source to a switch blade 139 which is swingably movable with 8 the knob pointer 139. Stationary contacts and 141' are associated with the fixed pointers or marks 140 and 141, respectively. The parts 139', 140' and 141' obviously constitute elements of the switch 138. A conductor 176 leads from the contact 140 to the switch 154 and is connected to its blade 155. A conductor 177 leads from one contact 178 of the switch 154 to a contact 179 of the motor 47. A conductor 180 extends from the contact 141' to a contact 181 of the motor 47. The other fixed contact 182 of the switch 154 is connected to the conductor 180. A negative conductor 183 of the electric circuit leads from the negative contact 184 of the motor 47 back to the current source. The positions of the switches 138 and 154 in FIGURE 14 correspond to the positions of said switches in FIGURES 4 and 3, respectively. Thus, with the parts positioned as shown in FIG- URE 14 the impeller 83 is turning counterclockwise (FIG- URE 3) for normal operation of the system as previously described. When sufiicient pressure builds up, as previously described, to distend diaphragms and 146, the switch blade will be moved out of engagement with the contact 178 to break the electrical connection to the motor contact 179, and will move into engagement with the contact 182 to complete an electrical connection to the motor through its contact 181 for reversing the motor 47 to drive the impeller 83 clockwise to effect the backwashing cycle.

For systems 15 utilizing large filters, the pump 31 may be made in larger sizes and equipped with an impeller 158, as illustrated in FIGURES 11, 12 and 13, in lieu of the single shroud, fixed radical vane impeller 83. The impeller 158 has a hub 159 and rear shroud 160, as in the impeller 83. Stationary stubs or primary vanes 161 are secured to or cast integral with the forward side of the shroud 160, around the hub 159 in circumferentially spaced apart relation to one another. The vanes 161 have corresponding convexly rounded side walls 162 and concavely arced outer ends 163. A front shroud 164 is preferably cast integral with front faces of the vanes 161 and extends to the inner ends of said vanes, and has at it inner edge an outwardly projecting annular apron 165.

A pivoted secondary vane 166 forms an extension of each primary vane 161 and is swingably mounted on a screw 167 which extends through parts of the shrouds and 164 and turnably through an opening 168 of the secondary vane, which is disposed centrally of a rounded inner portion 169 of the secondary vane and which fits conformably in the recessed outer end 163 of the primary vane. Each secondary vane 166 has convexly rounded side edges 170 which merge with one another at the outer end of the secondary vane and which form continuations of the side edges 162 of the primary vane. The shrouds 160 and 164 cooperate with one another and with the primary vanes to form passages 171 between the adjacent edges or walls 162 of adjacent primary vanes 161. The recessed outer end 163 with the outer ends of the side walls 162 form stops 172 for limiting swinging movement of the secondary vanes 166 through an arc as indicated by the arrow-tipped line 173 of FIGURE 11. The peripheries of the shrouds 160 and 164 may be connected together by tie elements 174 which are disposed beyond the extremiies of swinging movement of the secondary vanes 166, as seen in FIGURE 11.

Assuming that the impeller 158 is revolving counterclockwise, as seen in FIGURE 11, the liquid being pumped will be drawn inwardly through the apron and expelled radially through the passages 171 between the shrouds 160 and 164. The leading walls 162 of the primary vanes 161 will direct the outwardly flowing liquid at a steep inclination, since the speed of travel of said vanes is much less than the speed of movement of the impeller at its periphery and less power is required so that a higher angle of water entrance can be taken advantage of and which angle gradually diminishes toward the outer ends of the convexly rounded walls 162. The

walls 162 direct the water onto the leading side edges or walls 170 of the secondary vanes 166, all of which secondary vanes will be disposed in trailing positions relative to the primary vanes, as seen in full lines in FIG- URE 11, and parts of the rounded inner ends 169 and said leading walls 170 will provide a substantially continuous path for the liquid from the leading walls 162 and in a backward slope. When the direction of rotation of the impeller 158 is reversed, all of the secondary vanes will assume positions inclined in the opposite direction or as shown in dotted lines by one of the vanes 166 in FIGURE 11. Thus, the secondary vanes by being capable of automatically changing their water departure angle, automatically, when the impeller is reversed, provide backward sloping vanes, in either direction of rotation of the impeller, so that greater efficiency from the pump is realized, and the pump is enabled to produce greater volume and higher pressure by utilizing impellers of larger diameters and without a proportionate increase in the amount of power required to operate the impeller.

Various other modifications and changes are contemplated and may be resorted to, without departing from the function or scope of the invention as hereinafter de fined by the appended claims.

We claim as our invention:

1. A recirculating system comprising a liquid source, a reversible centrifugal pump including an impeller, a reversible motor for driving the impeller in either direction, a first conduit leading from the liquid source to the pump, a second conduit extending between the pump and liquid source, said motor driving the impeller in one direction for drawing the liquid from the liquid source through said first conduit to the pump and for returning the liquid from the pump through the second conduit to the liquid source, said motor driving the impeller in the opposite direction for drawing the liquid from the liquid source to the pump through the second conduit and for conveying the liquid from the pump through said first conduit, a filter interposed in said second conduit for filtering the liquid being returned to the liquid source therethrough from the pump, said centrifugal pump including a first chamber connected to said first conduit, a second chamber connected to said second conduit, an impeller inlet port opening axially toward the impeller, a supply passage leading from each chamber to said inlet port, a discharge passage leading from the impeller to each chamber, a valve located in each chamber, and means in each of said chambers responsive to a pressure variation in the chamber thereof for actuating the valve of said chamber for closing either the discharge passage or the supply passage of said chamber whereby when the supply passage of one chamber is closed by the valve thereof, the discharge passage of the other chamber will be closed by its valve, and pressure responsive switch means communicating with said second chamber and responsive to a pressure build-up therein for automatically reversing the motor to reverse the impeller for causing the liquid to be drawn by the pump through said second conduit, and means acting on the switch means for maintaining the motor reversed for a predetermined time interval.

2. A recirculating system comprising a liquid source, a reversible centrifugal pump including an impeller, a reversible motor for driving the impeller in either direction, a first conduit leading from the liquid source to the pump, a second conduit extending between the pump and liquid source, said motor driving the impeller in one direction for drawing the liquid from the liquid source through said first conduit to the pump and for returning the liquid from the pump through the second conduit to the liquid source, said motor driving the impeller in the opposite direction for drawing the liquid from the liquid source to the pump through the second conduit and for conveying the liquid from the pump through said first conduit, a filter interposed in said second conduit for filtering the liquid being returned to the liquid source therethrough 1t) 1 from the pump, said centrifugal pump including a casing having a portion in which the impeller is disposed and provided with an inlet port disposed to open axially toward the impeller, said casing having separate chambers, a separate discharge passage formed in the casing and leading from said impeller to each chamber, one of said chambers communicating with said first conduit and said other chamber communicating with said second conduit, said casing having a separate supply passage leading from said chambers to said inlet port, and each of said chambers having a valve for closing either the supply passage or discharge passage thereof and means in each chamber responsive to a pressure variation within said chamber for actuating the valve thereof whereby when the valve of one chamber is closing the supply passage thereof, the discharge passage of the other chamber will be closed by the other valve, and pressure responsive switch means communicating with said other chamber and responsive to a pressure build-up therein for automatically reversing the motor to reverse the impeller for causing the liquid to be drawn by the pump through said second conduit, and means acting on the switching means for maintaining the motor reversed for a predetermined time interval.

3. A recirculating system as in claim 2, each of said chambers having an elastic wall portion connected to the valve of said chamber and responsive to a pressure variation therein for positioning the valve thereof to close either the discharge passage or supply passage, respectively.

4. A recirculating system as in claim 3, said pump casing including a cover disposed over said elastic wall portions and having chambers in which said wall portions are received when distended relative to the chambers thereof, and said cover having a bypass passage connecting said cover chambers and combining therewith and with the elastic wall portions to form a pneumatic coupling between said valves of the two chambers whereby said valves are actuated to move simultaneously in opposite directions.

5. A centrifugal pump including a pump casing, said casing having a first port and a second port, an impeller disposed in said casing, a reversible motor for driving the impeller in either direction, said casing having an internally disposed inlet port communicating axially with the impeller, a separate supply passage extending between each of said first and second ports and the impeller inlet port, a separate discharge passage extending from the impeller to each of said first and second ports, a valve disposed in the casing adjacent each of said first and second ports, and means responsive to a pressure variation in said ports to cause the valve of one port to close the supply passage thereof when the other valve is closing the discharge passage of the other port.

6. A reversible centrifugal pump comprising a pump casing having a first port and a second port opening outwardly thereof, an impeller contained within said casing, a reversible motor for driving the impeller in either direction said casing including a discharge passageway partially surrounding the impeller and an inlet port communicating axially with the impeller, a separate supply passage leading from each of the first port and second port to said inlet port, said surrounding passageway having separate discharge ends communicating with said first port and second port, a valve individual to each of said first and second ports and to the supply passages and said discharge ends thereof, and means individual to the first port and second port and responsive to pressure variaelements disposed between and connected to said shrouds and combining therewith to define radially disposed passages, secondary vane elements mounted between and pivotally connected to said shrouds and forming swingably mounted extensions of said fixed vane elements, and 5 stop means limiting swinging movement of said pivoted vane elements relative to the fixed vane elements.

References Cited by the Examiner UNITED STATES PATENTS 1/1911 Heald 1033 12 Spicer 137-106 Tinker.

Rauscher 1032 Wagner 137-112 Engstrom 1033 Shelton et al 1033 Clark 210108 Saint Clair et a1. 210-169 X Fehlmann 210-108 Busquet 2301 14 Richards 210108 X REUBEN FRIEDMAN, Primary Examiner. RONALD R. WEAVER, HERBERT L. MARTIN,

Examiners. 

1. A RECIRCULATING SYSTEM COMPRISING A LIQUID SOURCE, A REVERSIBLE CENTRIFUGAL PUMP INCLUDING AN IMPELLER, A REVERSIBLE MOTOR FOR DRIVING THE IMPELLER IN EITHER DIRECTION, A FIRST CONDUIT LEADING FROMT HE LIQUID SOURCE TO THE PUMP, A SECOND CONDUIT EXTENDING BETWEEN THE PUMP AND LIQUID SOURCE, SAID MOTOR DRIVING THE IMPELLER IN ONE DIRECTION FOR THE DRAWING THE LIQUID FROM THE LIQUID SOURCE THROUGH SAID FIRST CONDUIT TO THE PUMP AND FOR RETURNING THE LIQUID FROM THE PUMP THROUGH THE SECOND CONDUIT TO THE LIQUID SOURCE, SAID MOTOR DRIVING THE IMPELLER IN THE OPPOSITE DIRECTION FOR DRAWING THE LIQUID FROM THE LIQUID SOURCE TO THE PUMP THROUGH THE SECOND CONDUIT AND FOR CONVEYING THE LIQUID FROM THE PUMP THROUGH SAID FIRST CONDUIT, A FILTER INTERPOSED IN SAID SECOND CONDUIT FOR FILTERING THE LIQUID BEING RETURNED TO THE LIQUID SOURCE THERETHROUGH FROM THE PUMP, SAID CENTRIFUGAL PUMP INCLUDING A FIRST CHAMBER CONNECTED TO SAID FIRST CONDUIT, A SECOND CHAMBER CONNECTED TO SAID SECOND CONDUIT AN IMPELLER INLET PORT OPENING AXIALLY FORWARD THE IMPELLER, A SUPPLY PASSAGE LEADING FROM EACH CHAMBER TO SAID INLET PORT, A DISCHARGE PASSAGE LEADING FROM THE IMPELLER TO EACH CHAMBER, A VALVE LOCATED IN EACH CHAMBER, AND MEANS IN EACH OF SAID CHAMBERS RESPONSIVE TO A PRESSURE VARIATION IN THE CHAMBER THEREOF FOR ACTUATING THE VALVE OF SAID CHAMBER FOR CLOSING EITHER THE DISCHARGE PASSAGE OR THE SUPPLY PASSAGE OF SAID CHAMBER WHEREBY WHEN THE SUPPLY PASSAGE OF ONE CHAMBER IS CLOSED BY THE VALVE THEREOF, THE DISCHARGE PASSAGE OF THE OTHER CHAMBER WILL BE CLOSED BY ITS VALVE, AND PRESSURE RESPONSIVE SWITCH MEANS COMMUNICATING WITH SAID SECOND CHAMBER AND RESPONSIVE TO A PRESSURE BUILD-UP THEREIN FOR AUTOMATICALLY REVERSING THE MOTOR TO REVERSE THE IMPELLER FOR CAUSING THE LIQUID TO BE DRAWN BY THE PUMP THROUGH SAID SECOND CONDUIT, AND MEANS ACTING ON THE SWITCH MEANS FOR MAINTAINING THE MOTOR REVERSED FOR A PREDETERMINED TIME INTERVAL.
 5. A CENTRIFUGAL PUMP INCLUDING A PUMP CASING, SAID CASING HAVING A FIRST PORT AND A SECOND PORT, AN IMPELLER DISPOSED IN SAID CASING, A REVERSIBLE MOTOR FOR DRIVING THE IMPELLER IN EITHER DIRECTION, SAID CASING HAVING AN INTERNALLY DISPOSED INLET PORT COMMUNICATING AXIALLY WITH THE IMPELLER, A SEPARATE SUPPLY PASSAGE EXTENDING BETWEEN EACH OF SAID FIRST AND SECOND PORTS AND THE IMPELLER INLET PORT, A SEPARATE DISCHARGE PASSAGE EXTENDING FROM THE IMPELLER TO EACH OF SAID FIRST AND SECOND PORTS, A VALVE DISPOSED IN THE CASING ADJACENT EACH OF SAID FIRST AND SECOND PORTS, AND MEANS RESPONSIVE TO A PRESSURE VARIATION IN SAID PORTS TO CAUSE THE VALVE OF ONE PORT TO CLOSE THE SUPPLY PASSAGE THEREOF WHEN THE OTHER VALVE IS CLOSING THE DISCHARGE PASSAGE OF THE OTHER PORT. 